This invention pertains to the art of seals and more specifically to a two piece radial lip type seal arrangement used between two members which rotate relative to each other and which permits the passage of a fluid medium therethrough.
Two-element lip-type seal arrangements for use between two relatively rotatable members are known in the prior art as represented by U.S. Pat. No. 4,185,838. Seal arrangements of this type are used to prevent the entrance of contaminants into an area located between the two relatively rotatable members. The use of a two-element seal arrangement is highly advantageous since each element may be individually replaced if damaged. Unfortunately, the configuration of the seal arrangement in the above mentioned patent has a complex shape thereby reducing the allowable tolerances during manufacturing of these seal elements. The seal arrangement in the above mentioned patent does not permit the passage of air therethrough and due to its complex shape, the arrangement cannot be readily modified to perform this function.
The seals in U.S. Pat. Nos. 4,071,076 and 4,440,401 are provided with holes therethrough. In the '076 patent, the holes are provided in the seal in order to allow air to pass therethrough. This air, however, is used to provide a cooling effect. In the '401 patent, the holes are provided through the seals for lubrication purposes.
There exists a need for a seal arrangement which can be utilized between two relatively rotatable members, which is composed of two seal elements which may be individually replaced if damaged, and will permit the flow of a fluid medium between the relatively rotatable members through the seal assembly. Such a seal arrangement can be utilized in various arts, for example in combination with a tire inflation system as disclosed in U.S. Pat. No. 4,498,709.
It is therefore the object of the present invention to provide a seal arrangement capable of transmitting a pressurized fluid medium from a passage in one member, through the seal, into a passage of another member which rotates relative to the first member. The seal arrangement must prevent the leakage of the pressurized fluid medium through the seals, provide a seal which prevents the ingress of contaminants into the sealed area, and minimize the drag between the two relatively rotatable members. It is a further object of the present invention to provide a seal arrangement which may be readilly serviceable, will provide for an easy assembly and which will be reliable.